High-frequency circuit and transmission and reception circuit using high-frequency circuit

Abstract

The present disclosure provides a high-frequency circuit including a matching circuit capable of adjusting the input/output impedance of a high-frequency device to an optimal value, even if the high-frequency device includes a circuit element whose input/output impedance varies upon the variation in the operating frequency, and provides a transmission and reception circuit including the high-frequency circuit. The high-frequency circuit includes a first high-frequency device, a second high-frequency device electrically connected to the first high-frequency device, and a matching circuit connected between the first high-frequency device 1 and the second high-frequency device. At least one of the first high-frequency device 1 and the second high-frequency device includes a variable device and has a changeable operating frequency. The matching circuit includes at least one variable device capable of performing impedance matching in accordance with operating frequencies of the first high-frequency device and the second high-frequency device.

Description

BACKGROUNDTechnical Field[0001]The present disclosure relates to a high-frequency circuit including a matching circuit capable of adjusting the input / output impedance of a high-frequency device to an optimal value even if an operating frequency varies, and relates to a transmission and reception circuit using the high-frequency circuit.[0002]In electronic components, in the case where electrical signals on a transmitter side in a transmission path have a constant power, if the output impedance of a transmitter circuit and the input impedance of a receiver circuit are made to be equal to each other, the receiver circuit obtains the maximum power. Accordingly, it is necessary to make those impedances equal to each other (hereinafter referred to as “to perform impedance matching”) for efficient transmission.[0003]In the case where impedance matching is not performed sufficiently, the receiver circuit cannot obtain the desired maximum output. In a high-frequency circuit, in particular, ...

AI Technical Summary

Benefits of technology

[0018]In the above configuration, two high-frequency circuits are connected to the first high-frequency device, and each of the high-frequency circuits is the above-described high-frequency circuit. The first high-frequency device is a wide-band circulator. An antenna is connected to the first high-frequency device. One of the high-frequency circuits functions as a transmitter circuit, and the other of the high-frequency circuits functions as a receiver circuit. Accordingly, even if the antenna is shared between the transmitter circuit and the receiver circuit, it is possible to reliably perform impedance matching in accordance with the variation in the operating frequency of the variable filter and to suppress degradation in reception characteristics.

Problems solved by technology

However, there has been a problem as follows.

Accordingly, impedance matching cannot be performed sufficiently between the variable BPF and a circulator.

Accordingly, impedance matching cannot be performed sufficiently, which may result in generation of various characteristics (e.g., increase in transmission loss and degradation in reception sensitivity).

That is, there has been a problem as follows.

Even if a high-frequency device that can be adapted to various operating frequencies is realized, it is not possible to embody a high-frequency circuit adapted to various operating frequencies unless a matching circuit that connects the high-frequency device and another device to each other is adapted to various operating frequencies.

Images